This invention relates to a manually releasable fastener which may be substituted for conventional bolt and nut fasteners that are used for securing together the adjacent ends of conventional segment type pipe couplings.
A conventional type of pipe coupling comprises two or more curved segments which are assembled together end to end to encircle and couple the adjacent ends of a pair of aligned pipes. Typically, such couplings are provided with integral, radially outwardly extending lugs on the ends of the curved segments. These lugs are provided with bolt holes through which bolts are extended and fastened by nuts for securing the segments together to form the circular or ring-like coupling. In such couplings, both ends of each segment may be formed with bolt receiving lugs. Adjacent lugs are secured together with conventional bolts and nuts. Optionally, some of the segments may be provided with hinge components for hingedly connecting that segment to the end of its adjacent segment. These bolts and nuts may be used to fasten the lugs on the opposite sides of segments. Examples of such couplings are described and illustrated in U.S. Pat. No. 4,915,418 to Josef Palatchy on Apr. 10, 1990 for a "Hinged Pipe Coupling", U.S. Pat. No. 4,966,395 issued to Thomas R. Hendrickson on Oct. 30, 1990 for a "Rigid or Flexible Coupling for Pipes", and U.S. Pat. No. 5,018,768 issued to Josef Palatchy on May 28, 1992 for a "Pipe Coupling Hinge".
Such pipe couplings generally comprise curved segments that are U-shaped in cross-section with side walls or legs that extend radially inwardly from a band-like base. The inner free edges of the legs form keys or tenons which fit into grooves cut in the pipes, near the ends of the pipes.
A rubber-like gasket is arranged within the space or channel formed by U-shaped coupling segments. The gasket encircles and seals the adjacent ends of the pipes when the keys are placed within the pipe grooves. Such couplings are typically used for water lines or pipe lines for conducting other fluid or gases. By way of example, water lines may be formed of a number of pipe sections coupled end to end. Each pipe section is provided with grooves near its ends and the pairs of pipe ends are arranged closely adjacent to each other. The coupling is then positioned around a pair of adjacent pipe ends and is secured in place to form a coupled joint.
Whether the segments are fastened together at one end by a hinge arrangement and at the opposite end by bolt and nut fasteners or whether the segments are fastened together entirely by bolt and nut fasteners, the segments must be manually positioned around the pipe ends. Then considerable time is involved in manipulating and fastening the bolt and nut fasteners. Although the time is not great for any one bolt and nut fastener, in the aggregate where numerous couplings are used, as for example, in a water line in a building, a considerable amount of time is required on the part of the plumbing installer. Hence, it is desirable to have a coupling system in which the segments of a coupling can be manually assembled rapidly, without the need of wrenches or other tools. To meet that need, prior couplings that are commercially available are provided with toggle or lever types of fasteners for interlocking adjacent ends of coupling segments. Examples of such devices are shown in U.S. Pat. No. 4,123,095 issued to Theodore A. Stehlin on Oct. 31, 1978 for a "Pipe Clamp Having An Overcenter Toggle", U.S. Pat. No. 4,561,678 issued to Donald R. Kunsman on Dec. 31, 1985 for a "Pipe Coupling" and Swiss Pat. No. 390,637 granted to Societe de Constructions d'Appareils Mecaniques Inoxydables on Apr. 15, 1965.
Segmented pipe couplings that use bolt fasteners are relatively inexpensive to manufacture. In contrast, pipe couplings that use toggle fasteners, particularly where made with sufficient strength and rigidity for coupling relatively large pipes, are considerably more expensive to produce. Thus, it would be desirable to have available, on a plumbing contracting job site, relatively inexpensive bolt-type fastened couplings with the toggle-type fasteners and without the required expense for a toggle type coupling.
The invention herein relates to a fastener, similar to a toggle-type locking fastener, which may be manufactured and stored as an independent unit, and which may be substituted for the typical bolt and nut fastener in a conventional bolt type coupling so as to provide the low cost benefit of the bolt-type coupling with the high speed, manual assembly ability of the toggle-type coupling.